This invention relates to a process for preparing 6-substituted 4-chromanones from phenolic acrylate ester compounds derivable from para-substituted phenolic compounds and beta-unsubstituted acrylic acid compounds which are esterifiable therewith. The 6substituted 4-chromanones prepared by the process of this invention are useful as intermediates for preparing pharmaceutical agents.
Preparation of 4-chromanones via condensation of beta-substituted, beta,beta-disubstituted and alpha, beta-disubstituted acrylic acids with phenolic compounds in anhydrous hydrogen fluoride is disclosed by Offe and Barkow in Chem. Ber. 80, 458 (1947), hereinafter Offe I. However, Offe I does not disclose such preparation using beta-unsubstituted acrylic acids. On the contrary, Offe I discloses that it is not practicable to use phenol and acrylilc acid as raw materials. Similarly, Amakasu and Sato indicate in J. Org. Chem. 31, 1433 (1966) that 4-chromanones are not obtainable via reaction of acrylic acid or alpha-monosubstituted acrylic acid with phenols.